As portable electronic devices become more compact, and the number of functions performed by a given device increase, it has become a significant challenge to design a user interface that allows users to easily interact with a multifunction device. This challenge is particular significant for handheld portable devices, which have much smaller screens than desktop or laptop computers. This situation is unfortunate because the user interface is the gateway through which users receive not only content but also responses to user actions or behaviors, including user attempts to access a device's features, tools, and functions. Some portable communication devices (e.g., mobile telephones, sometimes called mobile phones, cell phones, cellular telephones, and the like) have resorted to adding more pushbuttons, increasing the density of push buttons, overloading the functions of push buttons, or using complex menu systems to allow a user to access, store and manipulate data. These conventional user interfaces often result in complicated key sequences and menu hierarchies that must be memorized by the user.
Many conventional user interfaces, such as those that include physical pushbuttons, are also inflexible. This may prevent a user interface from being configured and/or adapted by either an application running on the portable device or by users. When coupled with the time consuming requirement to memorize multiple key sequences and menu hierarchies, and the difficulty in activating a desired pushbutton, such inflexibility is frustrating to most users.
In particular, it is slow and tedious to navigate in structured electronic documents (e.g., web pages) in portable electronic devices with small screens using conventional input devices (e.g., 5-way toggle switches). Moreover, it is cumbersome to control and view multimedia content within such documents on portable electronic devices.
Accordingly, there is a need for portable electronic devices with more transparent and intuitive user interfaces for viewing and navigating structured electronic documents and multimedia content within such documents. Such interfaces increase the effectiveness, efficiency and user satisfaction with activities like web browsing on portable electronic devices.